In a conventional type of glassware forming machine known as an `I.S. machine`, several identical sections, usually eight to ten, but sometimes as many as 16, are mounted side by side and operate, cyclically but in off set timed relationship, to make glass containers. Each section normally contains more than one mould for the making of such containers; usually two or three but increasingly commonly four: the machines are consequently described as double-, triple- or quadruple- gob machines. In the operation of each section the requisite number of gobs of molten glass are provided to a set of parison moulds, in each of which a parison is formed, and the set of parisons is transferred to a set of blow moulds in which they are blown to the required shape. When the containers have been formed they are removed from the blow moulds by a take out device, which picks up the containers and transfers them, usually to a dead plate on which they are cooled, and from which they are pushed out onto a conveyor.
A typical take out device is shown in GB 1274730. This shows a take out device, for use with a double gob glassware forming machine, comprising two take out tongs, a support for the take out tongs and mechanism arranged to move the support to carry the tongs between a pick up position in which the tongs may pick up moulded glass articles from the moulds of the machine and a deposit position in which the tongs may deposit the glass articles for example at a cooling station or dead plate.
It will be understood that when such a take out device is in use, the spacing of the take out tongs is determined by the spacing of the moulds, and thus the spacing of the moulds determines the spacing of the moulded articles on the dead plate. Conventional push out mechanisms pushing the moulded articles onto a conveyor from the dead plate may, by appropriate spacing of the pusher fingers, alter the spacing of the moulded articles on the conveyor from that on the dead plate, but the amount by which this can be done is severely restricted by the size and spacing of the containers and the need to position the fingers between the containers; this constraint is greater in a three or four gob machine than with a double gob machine. Also if an attempt is made to make a substantial change to the spacing, one at least of the pusher fingers will necessarily be moving quite fast when it first contacts the appropriate container, thus risking damaging the container.
With increasing use of multi gob machines and efforts to increase the rate of operation of the glassware forming machines, conveyor speeds also have to increase; it is however desirable to have the conveyor speed as low as possible, partly for economy of operation, but also because with increasing conveyor speeds problems of instability of containers on the conveyor increase. For this reason it is often desirable to obtain a spacing of containers on the conveyor which is less than the spacing of the moulds.
With certain machines, the widths of a section of the machine is in fact greater than the distance necessary to accommodate the containers removed from the section. In these cases it is sometimes desirable to ensure that the containers are placed on the conveyor with a spacing which is more than that between the spacing of the moulds, to ensure that the containers on the conveyor are all equally spaced, thus to provide for uniformity of conditions of the containers on the conveyor and for ease of handling in subsequent operations.
In EPA-0455331, a take out device for use with a multi gob glassware forming machine is described which comprises at least two take out tongs, a support for the tongs, mechanism arranged to move the tongs between a pick up position, in which the tongs may pick up moulded glass articles from moulds of the machine and a deposit position in which the tongs may deposit the glass articles, for example onto a dead plate, where at least one of the tongs is movably mounted on the support and moving mechanism is provided to move such movable tong between a spacing from its adjacent tong appropriate to the spacing of the moulds when the tongs are in the pick up position to a different spacing when the tongs are in a deposit position. The moving mechanism comprises a pneumatically operated piston and cylinder device. While such a device may operate satisfactorily, it is somewhat expensive in construction.
It is one of the objects of the present invention to provide an improved take out device for use with a multi-gob glassware forming machine which enables the spacing of containers of the conveyor to be varied from the spacing of the containers in the moulds of the machine.